The invention relates generally to a temperature control system and, more particularly, to a refrigeration system specifically suited for the storage of frozen parenteral solution filled containers.
In blood bank storage facilities the life expectancy of stored blood is significantly affected by the resident storage temperature. Experimental evidence indicates that the usual life of the stored blood is reduced substantially by variations of storage temperature from an optimum 4.degree. C. Consequently, blood bank storage facilities rely on well controlled temperature chambers with well designed and controlled temperature profiles that strive for good temperature uniformity throughout the storage area. However, air flow conditions within the facility depend upon the storage density that is in turn affected by a user loading and unloading of the blood containers. For that reason, existing storage facilities provide a substantially variable temperature profile that significantly reduces both the life and quality of the stored blood.
Another problem associated with blood bank facilities is the ever present possibility of intermittent periods in which a refrigeration system becomes dysfunctional exposing the blood contents to widely varying storage temperatures. Since such occurences will substantially degrade the quality of the stored blood, reliable temperature monitoring is essential. To assure that the refrigeration system is functioning correctly, agencies such as the Red Cross require careful, frequent calibration checkes which are performed manually. Such tests generally are made daily and typically entail temperature tests with thermometers and atests of fault detection systems by alternately subjecting temperature sensors to ice and warm water baths. Obviously, such manual test procedures are both labor intensive and subject to error.
The object of this invention, therefore, is to provide a blood bag storage facility in which storage temperature is continuously monitored, indications of system malfunction are provided automatically and periodic automatic integrity tests are made of the monitoring systems.